In conventional reciprocating pump units of this kind, the linear electric motor comprises an annular stator or drive member co-operating with a concentric annular "rotor" or reaction plate or driven member which is coupled with or which constitutes the reciprocating pump element.
It is an object of the invention to provide a pump unit driven by a linear electric motor of space-efficient configuration.
It is also an object of the invention to provide a control system for a pump driven by a linear electric motor which affords high efficiency operation.